The present invention relates generally to lift assemblies, such as those used to raise and lower scenery, props, and lighting on a stage.
Performance venues such as theaters, arenas, concert halls, auditoriums, schools, clubs, convention centers, and television studios can employ battens or trusses to suspend, elevate, and/or lower lighting, scenery, draperies, and other equipment that can be moved relative to a stage or floor. These battens are often raised or lowered by lift systems.
Conventional lift systems commonly include an overhead pulley, or loft block, supported by an overhead building support. Ropes or cables extend from the batten and through the loft blocks to a drive mechanism that facilitates movement of the cables. Such drive mechanisms often include a motor-driven drum that winds and unwinds the cables.
In order to insure that the lift system does not exceed capacity, some lift systems include means for measuring the load on the system. In the event that the load is exceeded, the motor can be deactivated or a warning can be generated.